With her arm stuck in the door of a speeding car, Leah W. Ulbrich was being dragged to her death when a woman standing on a corner in Hartford's South End noticed the hideous spectacle and reached for an emergency call box to notify the police. More than six years later, police want that woman to come forward. In an effort to jump-start an investigation that has reached a frustrating impasse, state and local law enforcement officials are making an appeal to a woman who alerted police over the call box at the corner of Wethersfield Avenue and East Elliott Street in the early morning hours of Oct. 29, 1995. ``We know whoever it was, was alarmed enough to make a call to the police, so we hope she will now be willing to contact us and help bring the killer to justice,'' said Lt. Paul Hammick, head of the Hartford Police Department's major crimes division. Police have set up a special tip line and are encouraging anyone with information about Ulbrich's homicide to call. The number is 860-548-0606. To provide further incentive, officials also have announced a $50,000 reward for information leading to the arrest and conviction of Ulbrich's killer. Gov. John G. Rowland recently approved a request to increase the reward amount from the $20,000 that had been authorized shortly after the killing. The 24-year-old Ulbrich, a mother of two from Wallingford, was dragged by a car for more than four miles along several Hartford streets before her mangled body finally was deposited in a gutter off Jordan Lane in Wethersfield. Witnesses told police Ulbrich apparently was talking to a man in a mid-size sedan, either a Nissan Altima or Maxima, when she either was pushed from the car or tried to escape. Her arm got entangled in a seat belt as the car drove off, witnesses said.Responding police officers were able to locate Ulbrich's remains after following a trail of blood and flesh left behind as she was dragged, police said. ``I was working as a patrol officer then, and I remember responding to that case,'' Hammick said. ``It was one of the most horrible things I've ever seen. No one deserves to die like that, and it's particularly upsetting to think that the man responsible is still out there, living life as usual.'' Police received several other 911 calls from alarmed witnesses, Hammick said. Most of those witnesses eventually provided statements to detectives, but the woman who used the call box never came forward. ``From where she was positioned, it's possible she may have seen the driver or the car in much more detail than others did,'' he said. ``We really need to hear from her.'' Police also released new details of the crime. Among Ulbrich's remains, Hammick said, investigators found a cord that had been ripped from an electronic device inside the car. He said detectives hope someone may remember the cord or remember someone who had to make repairs to an electronic car device in the days after the killing. Police did not say specifically what the device was.Police aren't the only ones desperate for a break in the case. Ulbrich's father, Robert Baskin, said his family has had difficulty putting her death behind them while her killer remains at large. ``Her kids are getting to the age where they have a lot of questions about what happened to her,'' he said. ``It would be a great relief if we could tell them that the man responsible has been apprehended and will face the consequences.'' Baskin said his daughter had a history of drug abuse, but he insisted that she had been on the road to recovery when she was killed. ``She had been through about a year of rehabilitation and was really starting to take control of her life,'' he said. Ulbrich was divorced. Her children, a 12-year-old boy and 10-year-old girl, are being raised by Ulbrich's mother, Baskin said. ``People who knew her know what a wonderfully creative and expressive person she was,'' he said. ``This ... was someone's daughter, someone's mother.''